Polyethylene: What Is It And What Is It Made Of? Application And Products, Physical Properties And Production, Production Of Extruded And Other Material

2024 Author: Beatrice Philips | [email protected]. Last modified: 2023-12-16 05:33

Today the chemical industry is one of the fastest growing. Researchers are working on the development of the latest scientific developments, in particular, on the creation of a variety of innovative materials. One of the most popular among them is polyethylene. Consider the features, unique properties and features of polyethylene, as well as its scope.

What it is?

First of all, you should figure out what polyethylene is. In fact, this material is a thermoplastic ethylene polymer . It can be categorized as a polyolefin. The definition of polyethylene includes the designation that, from a chemical point of view, a given material is an organic compound, and its molecules have a significant length.

If we talk about the external characteristics of the material, then it is most often presented in the form of thin sheets that can be colorless or white . Polyethylene is quite hard to the touch. It is quite common as a raw material and is used for a wide variety of purposes.

The scientists who invented polyethylene do not insist that the material is ideal. Like any other chemical compound, it has a number of unique properties that are both positive and negative.

Let's consider them in more detail.

The advantages of polyethylene include the following characteristics:

• a high level of strength (in this regard, we mean the fact that the material is able to withstand mechanical damage and other negative environmental influences);
• elasticity;
• waterproofness;
• ease of use;
• low level of thermal conductivity;
• safety for humans (polyethylene does not emit substances that could harm human health);
• affordable price;
• wide range of;
• varied designs and much more.

But even despite such a large number of positive characteristics, it is necessary to remember about the existing shortcomings:

• destruction under the influence of direct sunlight;
• relative fragility;
• environmental pollution, which is a key negative characteristic of the material.

How and from what are they made?

The method of obtaining and the process of producing polyethylene is of particular interest to researchers. So, the discussed chemical compound is obtained from ethylene. The raw material is subjected to a mandatory polymerization process.

Initially, polyethylene consists of granules, the size of which ranges from 2 to 5 millimeters. The compound gets its final composition through heat treatment processes, which are carried out using specially designed equipment.

At the same time, today, experts in the field of chemistry distinguish several types of polyethylene, each of which is made according to an individual technology.

Properties

In order to familiarize yourself with the material in more detail, you should analyze its distinctive characteristics (including physical and chemical). After all, polyethylene has special properties that distinguish it from any other compound.

So, the main features of the material include:

• as a general rule, polyethylene is transparent (this applies only to a pure chemical compound, devoid of any impurities), during the dyeing process, the material can acquire any other shades (black, white, red and many others);
• the material is solid in structure;
• the crystallization process of the material is carried out at a temperature from -60 to -369 degrees Celsius;
• lack of smell;
• small indicators of mass;
• the density of the material is unstable, it depends on how the polyethylene was obtained;
• chemical compounds have the properties of a shock absorber;
• low level of adhesion;
• low coefficient of friction;
• waterproofness;
• polyethylene undergoes softening processes at temperatures from +80 to +120 degrees Celsius;
• resistance to low temperatures;
• flexibility;
• dielectric characteristics;
• steam and waterproofing;
• biological inertness;
• thermal conductivity;
• during decomposition, polyethylene does not emit substances that are harmful to humans;
• resistance to aggressive chemical compounds.

The properties of polyethylene for the most part determine the areas of its use.

Overview of Density Views

Today there are many types of polyethylene. So, on the market you can find extruded, low molecular weight, bubble, roll, high strength and high modulus material. Accordingly, when choosing polyethylene, you must pay close attention to the labeling.

For the convenience of the user, manufacturers have adopted a classification of the compound into several categories . Consider the distinctive characteristics and features of each of them.

High

For the production of high density polyethylene, a number of prerequisites are required. In particular, the air temperature should be in the range from 200 to 260 degrees Celsius, the pressure should not exceed 300 MPa . In addition, the presence of a catalyst is required, the function of which can be performed by oxygen or organic peroxide. The production procedure itself is carried out in an autoclave or tubular reactor.

With regard to the direct characteristics of the material, high density polyethylene is lightweight and elastic. It has pronounced dielectric characteristics. The peculiarity of the material is that such polyethylene is rather easy to be recycled.

Low

The conditions necessary to obtain low density polyethylene should be as follows:

• temperature indicators - 120-150 degrees Celsius;
• pressure level - 0, 1-2 MPa;
• the presence of a catalyst, such as Ziegler-Natta catalysts.

As a result of the polymerization process, a material is formed that allows cooling down to -80 degrees Celsius.

In addition, low density polyethylene is very light and elastic, and its surface has a characteristic gloss.

Middle

Medium density polyethylene is produced at a temperature of 100-120 degrees Celsius. In this case, the pressure should be at the level of 3-4 MPa, and it is recommended to use a mixture of TiCl4 and AlR3 as a reaction catalyst . It should be borne in mind that the final compound will form in flakes.

Thus, the existing varieties of polyethylene differ both in their properties and characteristics, and in the methods of production.

Popular manufacturers

Due to the fact that polyethylene is a material that is widespread, is popular and in demand among consumers, a large number of brands are engaged in its production. Let's consider the main ones.

Kazanorgsintez

On the territory of the Russian Federation, this company is one of the largest producers of polyethylene (and the range includes material of both low and high density). Despite the fact that this brand appeared on the market in 1950, the first batch of the product appeared only 13 years later . It is also important to note that the brand's assortment includes not only polyethylene, but also a number of other chemical compounds. As the name suggests, the company is located in Kazan.

Nizhnekamskneftekhim

The production facilities of the plant, as well as the products themselves from Nizhnekamskneftekhim, meet all modern technological requirements. The company's employees are focused on the implementation of innovative technologies and scientific developments . At the same time, only high-quality raw materials are used here. As for the distinctive characteristics of polyethylene from this company, it should be noted such properties as a high level of adhesion, smooth and transparent surface, compliance with international standards and many other positive qualities.

Stavrolen

This company is engaged in the production of a variety of petrochemical products. For the first time, Stavrolen produced polyethylene in powder form. The company's products correspond to the world level and are in demand among a wide range of consumers . Employees of the company use the method of polymerization in a gaseous state to obtain a chemical material.

Tomskneftekhim

The Tomskneftekhim company produces polyethylene using polymerization technology, which is characterized by high pressure in the reactor. It should be noted that the products manufactured by this brand are popular not only in the domestic market, but are also exported abroad . To create a raw material base, which is the starting point for the production of polyethylene, Tomskneftekhim is engaged in the processing of hydrocarbons (namely, liquefied gases and gasoline).

Angarsk Polymer Plant

The plant is engaged in the production of high-density polyethylene grade 10803-020 V / C. As for production volumes, the company produces about 300 tons of material in 1 year. Polyethylene of this brand is of high quality and has the appropriate certificates . The chemical compounds of this company are divided into 3 categories: superior, first and second grade. In terms of density, this material is at the level of 0.90 g / cm3. The elongation at break is 550%. Polyethylene "Angarsk Polymer Plant" is used for the manufacture of technical products, toys, packaging, agricultural goods and others.

Ufaorgsintez (Bashneft)

This enterprise is one of the oldest polyethylene production facilities on the territory of our state. The production of a polyethylene chemical compound within the framework of Ufaorgsintez (Bashneft) dates back to 1967. The company produces several different types of material that meet the needs of the market . Polyethylene of this trade mark is used to make technical goods, packaging for food and medicines, children's toys and other products.

Polymir

This company is located in Belarus. However, the company's products are widespread and popular far beyond the borders of this country. Polyethylene from "Polimir" maintains its competitiveness due to its high technological effectiveness of the production process, a wide range of products and high-quality raw materials . Speaking about the variety of material, it should be said that the company produces material of grades 10204-003, 10803020, 15803-020 and many others. Moreover, each of these brands is used for the production of various categories of products (for example, pipes, films, paper, dyes).

Gazprom neftekhim Salavat

Polyethylene production is carried out in several workshops of the plant. At the same time, low and high density material goes on sale. The location of the factory is Salavat, Republic of Bashkortostan. Ethylene, butene, hydrogen and hexane are used as starting materials.

Thus, on the territory of the Russian Federation there are a huge number of factories and factories that are professionally engaged in the manufacture of polyethylene . This fact proves that the material is widespread, popular and indispensable in many areas of human activity. At the same time, the domestic material is of high quality.

Application

As mentioned above, polyethylene is one of the most widespread and demanded materials, respectively, it is used in a large number of areas and for the production of various products.

Application of polyethylene:

production of dense food and technical film in rolls

production of containers and packaging products (for example, plastic bags)

manufacture of sewer pipes, as well as pipes for water supply

fabrication of a sheet for insulation (for example, electrical insulation)

creation of hot melt glue

production of heat insulators

This, of course, is not a complete list.

However, it should be borne in mind that the widespread use of polyethylene can adversely affect the ecological state of the environment.

The thing is that this material decomposes for a rather long period (in some cases, the material does not decompose at all) . This can lead to pollution of the atmosphere, the oceans and the planet as a whole, as well as to other negative consequences (for example, many animals die from eating polyethylene).

Disposal

Polyethylene can be either primary or secondary. This means that after the originally manufactured polyethylene product becomes unusable, it can be recycled and reused. Techniques such as extrusion, blow molding, injection molding and pneumatic molding are used to process polyethylene compounds.

As for the direct disposal process, it is most often the incineration method . However, as soon as the polyethylene is heated (for example, in direct sunlight), it releases volatile products. Accordingly, the process of formation of low-boiling compounds takes place.

Thus, the process of incineration of polyethylene by its characteristics and features is a complex chemical process.

Decomposition features

As already mentioned, polyethylene is a material that decomposes for a very long time, it will take many years to complete this process. At the same time, methods of biological decomposition of this chemical compound are becoming more and more popular today.

So, for the implementation of biodegradation processes, special molds Penicillium simplicissimum are used . With their help, polyethylene can be partially recycled within 90 days. However, in order for this process to be as effective as possible, the material must first be treated with nitric acid. In addition to the above type of bacteria, the use of the microorganisms Nocardia asteroides is also recommended. It should be borne in mind that the decomposition of polyethylene (even with the use of specific bacteria) can take several years (at least 8).

Polyethylene is a popular and demanded material that is used for various purposes. In its physical and chemical properties, it differs from many other materials, due to which it is widespread. At the same time, there are several varieties of it, each of which has its own unique characteristics.